By Dr. Priya Mendiratta

What we don't see still exists, perhaps despite the 7 billion population, many undiscovered treasures are still out there just on this planet.

Listening to Neil Tyson, my favorite astrophysicist, if the entire Universe's age was compressed into one calendar year, the life of documented human race would just be a second.

Recently we visited Blanchard Springs caverns: these are one of Arkansas State's treasures and most unusual underground caves located in the Ozark National Forest in Stone County in Northern Arkansas USA, located a short distance from Mountain Home. They are believed to have been formed, and continually changed, by an ongoing mountain spring that pours into a glassy-surfaced trout pond below the cave, called Mirror Lake.

Previously we had been here for a summer trip and it had taken over three hours to explore the entire cavern but the underground portion is closed during winters, so as not to disturb the 400,000 bats that are hibernating deep underground.

We were taken by elevator down to bowels of earth 21, stories below or approximately at a depth of 216 feet down under though at some places the cavern is 250 feet deep.

The cave was first perhaps discovered by Native Americans, and a body was discovered few decades ago around 1955, which was carbon dated and found to be 1100 years old, though not clear as to how without any flashlight someone ventured this far centuries ago.

This cavern was discovered by teenagers 14 and 16-year-olds, who took some long exposure photographs in the area they were hiking and were really not sure what they stumbled upon with just a flashlight, but on developing them they were shocked to see the surroundings and accidentally discovered it.

The locals knew about it as early as 1955, when it was called the half mile caves. The state tourism took another 8 years from when they were actually discovered and opened to the public in 1973 after making it safe for public viewing, lighting it up, making safe access and elevators to reach a depth of 200 feet.

A Czechoslovakian, opera house worker was hired especially and did an amazing job of lighting the cave, to give it the current stupendous appearance.

Some 50 million years ago water passed through limestone and collapsed the ceilings to form caverns, but current cavern was formed some 100,000 years ago and has been preserved intact essentially.

It is estimated that surrounding Ozarks may have up to 10,000 such caverns waiting to be discovered.

We took the shortest 1-hour tour available called the drip tour and entered a site called "the cathedral site" and was one of the most spectacular sites that only a personal experience can define better.

It appeared to be a scene akin to Indiana Jones movie "The raiders of the lost Ark".

There was beauty, awe and a sense of spirituality evoked at the marvelous treasures.

It was like one was surrounded by many Shiv linga( Hindu God Shiva's formation in a cylindrical form worshipped in Hindu Temples as a symbol of generative power) in different sizes glowing an amazing red, grey or white depending on the underlying mineral.

The iron oxide gave a red hue, manganese grey ones and white were calcite.

Calcite is a common constituent of sedimentary rocks, limestone, in particular, much of it is either precipitated or dissolved by ground water, it is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3)

Calcite deposits over 100 years and it grows a cubic inch, primarily by water dripping through caverns causes the calcite to continue growing.

The stalactites (grow from the top) the ceiling formations – grow long enough to connect with stalagmites (formation on the floor), they join to form columns.

The cave temperature year around is at 58-degree f and is100 percent humid. To reach the lower level there are some 700 steps and in the summer, this discovery trail takes 2-3 hours to explore.

A white-nose bats disease has killed or made bats extinct in many other caves globally, which is actually a fungus that prevents them from hibernating so they leave caves in winters only to freeze to death or die of hunger and fall off the sky out of sheer exhaustion, some may consider that a supernatural phenomenon in some parts of the World.

The forests around have been thinned some by conservation officials to decrease the fungus spreading in bats, and to help them survive by opening the canopy, and have been successful in this area in keeping them alive.

The only organism that grows in caves is Salamander, an amphibian that exists on bat drippings or bat poop or guano.

It is rumored that manganese is formed around a microorganism and presence on Mars of manganese might mean a sign of some life.

Interestingly the bats are sort of potty trained and poop in the same exact place or entire bat family does that for generations resulting in big bat black poop mountains in the cave called guano.

The guano or bat poop is used to make fertilizer as are rich in nitrogen, potassium and phosphate, even to make gun powderBat guano from the Mammoth Caves of Kentucky was used to make saltpetre, of the three key ingredients of black gunpowder, up until WWII and rumored ladies that it is used in cosmetics including mascara though lately all cosmetic companies have announced that to be false, saying that it is made from guanine which is obtained from fish gut.

Some formations look like a battleship, some like the opera house balcony, some resemble Indian Shiv Lingas, and some is left to your imagination.

The acid in hands can destroy the calcite growth making it loose the ability to grow, making it dry and chalky, so touching is forbidden, and tour guide does not let anyone step away from the path created to preserve the beauty of the cave. Also, a dry spell or drought can cause the lack of dripping and formations.

I wondered if the place was safe during a nuclear attack though cavern can house up to 29,000 people, the water and air would bring the nuclear effects into this depth even, in under a day.

The depth is surprisingly protected from earthquakes, though has an earthquake meter installed in ceilings and though several in the area, have caused destruction on the surface but none at the depth for centuries.

During summer, the tour guide takes for longer, 6-hour tours called the wild cave tours for some groups who are in good physical health through dark caves and one has to crawl through them to see more inner depths than was visible. Aaron Christopher was our wonderful guide through the trip.

It is true sometimes some such experiences are priceless, not found in books, but meant to just be felt and experienced with our senses, and continue to add on to our entire experience on earth.

Priya Mendiratta is a physician, an associate professor in geriatrics at University of Arkansas for Medical sciences at Little Rock Arkansas, USA.